只包含本身的ZIP文件？ [英] Zip-file that contains nothing but itself?

问题描述

只是出于好奇，是否存在一个有效的zip文件（根据格式规范），只包含自己？

换句话说， unzip 实现的函数有一个固定点？

我可以编写一个程序来搜索这样一个fix-

我也想过相反的情况，也就是如果 zip 有一个固定点，但可能是一个文件可以以不同的方式（不同的算法，不同的压缩级别等等）压缩，因此无论 f = zip（f）保存为某些文件 f 可能是依赖于实现。因为zip压缩是无损的，然而， unzip 的情况应该有一个正式的答案。

<有没有人探讨这个？

解决方案

您可以在这里阅读： http://research.swtch.com/2010/03/zip-files-all-way- down.html

您可以在这里找到 r.zip ，其中包含它自己。

Just out of curiosity, does there exist a valid zip-file (according to format spec) that, contains nothing but itself?

Put another way, does the function implemented by unzip have a fix-point?

Can I write a program to search for such a fix-point in a intelligent (not-exhaustive) way?

I've thought about the opposite as well, i.e. if zip has a fix-point, but presumably a file can be compressed in different ways (different algorithms, different levels of compression and so on), thus whether or not f = zip(f) holds for some file f is probably implementation dependent. Since the zip-compression is loss-less however, the case for unzip should probably have a "formal" answer.

Has anyone explored this? Any pointers to related URLs are appreciated.

解决方案

You can read about it here: http://research.swtch.com/2010/03/zip-files-all-way-down.html

Here you will find r.zip, which contains itself.

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